Control valves are used throughout an operating process, to modulate the flow of the fluid through conduits to meet process needs. The control valves perform in response to a signal from a control system to modulate fluid supply to the process according to the needs. It is imperative that the performance of each control valve is kept in check, especially in sensitive processes where slight variations in the supply may affect the output of the process.
Presently, as part of process monitoring and control functions, operators retrieve and interrelate vast amounts of data from the control system in order to build appropriate mental models of the process. Operators rely on these mental models to proactively diagnose control valve and loop performance to thereby evaluate a performance of the control valve. Operators experience plays a key role in the robustness of these mental models.
Different operators may have different sets of mental models, which are formed after years of experience with particular control valves. No consistency may exist when diagnosing and determining control valve and loop performance (especially between experienced and novice operators).
Comparing the operating statistics with that of the manufacturer provided statistics is not ideal as the manufacturer provided data does not take into account the installed characteristic of the valve.
Presently, offline stroke tests are performed to evaluate the performance of the control valves. This is not desirable, as the process will be adversely affected by the downtime during the offline stroke tests.
On the other hand, the performance of control valves must be constantly checked as performance variations of the control valves may be caused by leakage and/or bypass open situations. Should these situations not be arrested early, the extent of damage imparted to a process will be great.
It is an object of the present invention to eliminate or address one or more of the above problems.